Apparatus for and method of sizing, truing, straightening, and polishing metal rounds



Dec. 22, 1936. wmwogp, JR 2,065,166

APPARATUS FOR AND METHOD OF sums, mums,

STRAIGHTENING, AND rousxmxe METAL noumns Filed June 6, 1955 INVENTOR Patented Dec. 22, 1936 UNITED STATES PATIENT OFFICE- Application June 6, 1935, Serial No. 25,241

6 Claims.

This invention relates to apparatus for and a method of sizing, truing, straightening, and polishing metallic rounds, such as hot rolled bars, wire rods, pipes, tubes, and the like.

Throughout the specification and claims the various types of round stock which may be appropriately acted upon by my apparatus and method, will, for increased simplicity in expression, be termed simply rounds.

One object of my invention is to provide means of simple and rugged construction, capable of acting upon rounds accurately to size and to true the rounds to approximate mathematical roundness, and to straighten and polish them.

Another object of my invention is to provide a method of sizing, accurately rounding, straightening, and polishing rounds which may be performed to obtain at high production rate a finishing effect analogous to, but superior to, that obtainable by cold drawing.

In the accompanying drawing, Fig. I is a side elevation of a round-finishing installation, showing the primary features .of an installationembodying my invention.

Fig. II is a fragmentary plan view, showing the arrangement of the working elements of the installation with respect to each other, and showing the immediate driving means for the working elements.

Fig. III is a diagrammatic, longitudinal, vertical section, illustrating the guided passage of round stock through the working pass of the instrumentalities shown in Figs. I and 11.

Fig. IV is a diagrammatic plan view on an enlarged scale, illustrating the form of the working pass provided by the structure and arrangement of the working elements, and illustrating the bearing of the working elements upon the bar.

It is well known that round metallic stock,

herein comprehensively included by the term'.

rounds," comes from a hot mill in imperfect condition for many purposes. The rounds, as hot rolled, not only carry surface imperfections of the sort which may be removed by pickling, but are also inaccurately sized, and vary somewhat from a true circular cross section. A usual method of sizing and truing the rounds is to cold draw the stock in an installation known as a draw-bench. The cold drawing operation is slow and expensive, and involves the additional step of pointing the rounds for insertion into the sizing dies. As well as adding a step to the finishing operation, the pointing of solid rounds in creases scrap loss, since a substantial length of the pointed end is removed from the finished. stock. Also a cold drawing operation causes simultaneous flow of metal around the entire circumference of a. round, thus requiring the development of great power in the equipment for pulling the rounds through the dies.

Cold drawing presents the further disadvantage that scale pitting, leaving in the stock surface imperfections remaining after removal of scale by pickling, are deepened rather than worked out by a cold drawing operation.

Another method of finishing rounds is a cold rolling process, in which the rounds are passed between successive cooperating pairs of contoured cross rolls set at a relatively wide angle to the longitudinal center line of the round as it is passed through the machine. While such machines primarily act upon the high spots of a solid round, or a pipe or tube of substantial wall thickness, to cause the metal at the high spots to flow into the low spots on its circumference, thus tending to produce a round of accurate size and roundness, the sizing and truing efiect upon the stock is obtained in relatively slight degree only, as compared with the accuracy in sizing and rounding obtainable by a cold drawing process.

While in a cross-roll, cold-finishing, operation the rate of production is substantially higher than that obtainable by cold drawing, the speed of such machine is not high, as compared with other rolling operations, and it is generally necessary that a round be run more than once through a succession of cross roll scrolling and pressure passes.

A cold-finishing operation, conducted in accordance with my invention, so subjects the rounds to powerful compacting forces that they are brought to within very narrow tolerances as to size and cross-sectional accuracy at a high production rate. Even higher speed is obtainable in operations conducted in my apparatus solely to straighten and polish the rounds.

In the accompanying drawing reference numeral l designates a roll stand, in which are mounted two working discs 2 and 3, both of which are fully trunnioned in the roll stand by trunnions extending oppositely from the side faces of the discs. Disc 2 carries trunnions 4 and 5, lying. respectively in a neck-bearing 6 and thrust-bearing I. Disc 3 carries trunnions 8 and 9, lying respectively in a neck-bearing Ill, and thrustbearing II. The discs 2 and 3, which may be, and desirably are, relatively heavy, are mounted to present to each other their respective workand are so mounted that the axes of the two discs lie in intersecting planes.

Referring particularly to Figs. I and III of the drawing, it will be seen that the discs 2 and 3 are so mounted that the axis of each lies beyond the periphery of the other, and that the discs in their mounting overlap in a region lying between the axes of the discs. Because of the skew mounting of the discs, in intersecting planes, the opposed working faces'20 and of the discs form with each other a converging pass, in the region in which the discs overlap. The discs 2 and 3 are oppositely rotated, so that round stock introduced into, and passed through, the converging pass between the opposed working faces of the discs is carried longitudinally through the pass. The circular contact zones on the side working faces of the discs, because of their off-center contact with the rounds, also describe each a spiral path about the surface of a round, as it advances, rotating the round about its longitudinal axis. The mounting of the discs being such that the axis of each lies beyond the periphery of the other, the I overlapping of the discs is in a narrow zone extended but a short distance radially inward of the discs; The pass formed by such overlapping is thus one of high longitudinal lead,

. and resultantly one producing high progressive speed of the stock.

Under some conditions, and usually for those involving straightening and polishing only, it is desirable that the linear speed of the disc faces in their annular line of contact with the stock be equal.- This avoids a tendency to deeply scroll a round because of inequality in the action of the discs, producing a drag upon the round. More vigorous action is obtainable, conversely, by inequality in the linear speed at the points of tangency of the two disc faces with a round.

The driving means shown comprise shafts l2' and I 3, each of which has a flexible coupling [4 with the pinion shafts, or trunnions, l5 of a pair of meshing pinions l6 and [1. If pinions I6 and ll be identical, one of them being positively drivthe driving of the discs in opposite directions with equal angular velocity, and simplifies connections for driving the discs.

As shown in Fig. III, guides 2| are used to direct stock through the converging pass between the opposed side faces of the discs, along a pass line between the axes 22 and 23 of the discs. As shown, the discs are of equal diameter; and if, then, they be rotated at equal angular velocity, the linear speed at the points of contact of the two discs with the stock is equal at a median line between their axes. The guides 2| are shown as simple tubular elements for directing the passage of rods through the pass. It is to be understood, however, that, alternatively, guide rolls, or other suitable guiding means, may be employed.

It will be observed that the equal rotative angles, (see Fig. 111) made by the opposed working faces 20 and 30 of the discs with the longitudinal axis ofa round in the pass, are relatively slight, so that rounds advance through the pass between the discs at high speed. The compressive effect in the converging pass between the working faces of the discs may be none the less great. Since the contact points of tangency of the discs with a round describe a spiral course about the round, at any instant the discs have with the round point contact as the round progresses. The effect is to size and true the round by flow of metal from any regional high spots of the rounds into the low spots on its surface, the compacting effect of the discs on the, round undergoing the finishing operation, being emphasized by the point contact between the discs and the round.

It will be noted that the convergent pass between the opposed working faces of the discs is obtainable without ridging or otherwise contouring the faces of the discs. The working faces 20 and 30 of the discs may be, as shown, plane, save for a slight curvature at the junction between each of these faces and the curved peripheral faces of the discs to avoid presenting sharp cutting edges to the rounds. Since discs having plane faces may be used, itis possible to avoid the diiiiculty of forming and maintaining deeply contoured disc faces.

It is to be understood that the thrust bearings of the installation may be any of the forms of linearly and angularly adjustable thrust bearings, well known to those skilled in the art; in order that the apparatus may be accommodated to exert predetermined pressure on rounds of different diameter, and in order that the angularity of the pass may be varied.

Whereas the apparatus of my invention is purposed primarily for use in performing a cold finishing operation, it may be utilized as a hot finishing pass'in the final stages of hot rolling. Also, it may well be used to perform a finishing operation stock at a temperature intermediate atmospheric temperature and a hot rolling temperature.

I claim as my invention:

1. In cold rolling apparatus for accurately finishing round sections the combination of two discular rolls having their axes spaced from each other in intersecting planes and having the axis of each lying beyond the periphery of the other,

posed faces of the discs a converging pass in which high longitudinal lead of the discs on the stock and high progressive speed of the stock with respect to disc speed is obtained, means for rotating said discs about their axes in opposite directions of rotation, and means for introducing rounds into the converging pass between the overlapping regions of the disc faces.

2. Apparatus in accordance with claim 1 in which the means for introducing stock into the pass is arranged to introduce the stock along a line at which the stock-contacting points of the two discs move at equal linear speed.

3. In cold rolling apparatus for accurately finishing metallic rounds the combination of a' roll stand, two discular rolls mounted in opposition with their axes spaced from each other in intersecting planes and with the axes of each disc lying beyond the periphery of the other disc,

said discs in accommodation to high pressure operation both having trunnions extended at 15 both side faces thereof into bearings in the roll stand in such position that the trunnion of eacli disc lies beyond the periphery of the other disc and providing in the interval between their respective trunnions and'between their opposed faces a converging pass, and means for rotating said discs about their axes in opposite directions; the radius'of its trunnion defining for each disc the minimum distance between its axis and the periphery of the other disc.

4. Apparatus in accordance with the combination of claim 3 in which the two cooperative discs are both driveni'rom the same side of the roll stand. 1

5. Apparatus in accordance with the combination of claim 3 comprising additional means arranged to introduce round stock into the pass along a line at which the stock-contacting points of the two discs move at equal linear speed.

6. The method herein described of accurately finishing a round section between two discs which consists in entering it and passing it along a pass line on opposite sides of the centers of rotation of the two discs, causing the opposed discs to contact the stock in a converging pass while rotating the discs in opposite direction and at a relative speed to cause equal linear speed in the lines of contact of the two discs with the round, in response to the opposite rotation of said discs causing the round to advance through the pass rotating as it advances and as the opposite points of tangency of the disc faces with the round progress in a spiral course upon the surface of the round, and establishing with the stock tangential contact angles of value so much below ninety degrees as to render the component tending to cause progress of the stock relatively high with respect to the component tending to rotate the stock in rotating contact of the discs with the stock.

EDWARD W INWOOD, Jn. 

